Abstract: A check valve assembly for the forced gas cooling system of a vacuum heat treating furnace is disclosed. The check valve assembly includes a check valve for installation on the exterior of a hot zone wall in a vacuum heat treating furnace. The check valve includes a valve body forming an inlet, an outlet, and a channel extending longitudinally through the valve body. The valve body has an inner wall that forms a recess near the inlet. The channel contains a flap pivotally supported on a shaft that extends through the recess. The flap pivots in and out of the channel to permit a cooling gas to flow through the valve body in one direction while substantially preventing the flow of gas through the valve body in the opposite direction. The flap is operable between a closed position in which the flap extends into the channel to obstruct the channel, and an open position in which the flap is pivoted out of the channel and into the recess.

Abstract: The present arrangement provides for having the plenum divided into at least two sections. One section dumps quench gas from a first direction into the hot zone chamber during a first period and the other section dumps quench gas into the hot zone from an opposite direction during a second period whereby the cooling is relatively uniform. During the quenching operation the quenching gas is drawn from the hot zone chamber through a heat exchange and is returned therefrom to a loop through the hot zone chamber in touch with the workpiece. Direction flow gates control the alternate use of the two plenum.

Abstract: The present arrangement includes a removable, sealable plate located over a port in the side of a vacuum furnace chamber, which port lies opposite a heat exchange device. The heat exchanger is mounted on guide devices to enable it to be slideably withdrawn from the furnace chamber without causing injury to any other furnace parts located within the vacuum furnace chamber, such as the hot zone. The removable, sealable plate has major apertures therethrough to permit coolant pipes (eq. water pipes) to pass therethrough. Such feedthrough coolant pipes are sealed to provide integrity for the vacuum condition of the furnace. In addition the present arrangement includes a second sealable, removable plate located on a bonnet device which houses a fan motor. The grease fittings for such a fan motor are elongated and are accessible when the second plate is removed.

Abstract: The present arrangement includes a plurality of graphite support assemblies which serve to hold graphite heating elements of a graphite hot zone to be used with a vacuum furnace. Each of the support assemblies is designed to employ graphite bolts. Laminated graphite washers are located between the bolts and the graphite heating elements and between the graphite heating elements and the support assemblies so that the bolts do not loosen in response to cycles of hot and cold temperatures.

Abstract: The present device comprises an enclosing structure for a vacuum furnace hot zone. The enclosing structure, in a preferred embodiment, includes an outside wall (usually fabricated from stainless steel), and inside wall (usually fabricated from laminated graphite sheets) and layers of graphite felt located between the outside wall and the inside wall. The graphite felt is "cut back" so as to be shorter than both the outside wall and the inside wall, thereby creating a channel around the end of the enclosing structure. The present device further includes insert structure inserted into the channel and the insert structure comprises a backing of heat insulating rigidized material as well as a bonded front strip, in a preferred embodiment, fabricated from laminated graphite sheets. The insert seals and prevents any particles, emanating from the layers of loose fibered blanket of insulating material, from entering the hot zone, or other sections of the furnace, to contaminate the same.

Abstract: The present loading grid assembly includes a plurality of support bars which are held together by assembly support rods which lie orthogonal thereto. The assembly support rods are terminated in end blocks which have grooves formed therein and which are formed to be substantially symmetrical about the assemby support rods. Accordingly, the assembly can be turned over so that any sag which results from a load is reversed thereby providing wear on the upper and lower sides of the assembly. In addition, the present device includes post guides, spacer blocks, stacking posts and interlocking members. The post guides fit into the grooves of the end blocks and into grooves of the stacking posts to provide a support means for a second tier of support bars. The spacer blocks fit over the assembly support rods to define a changeable separation between adjacent support bars while the interlocking members securely separate adjacent bars and provide further vertical support to an assembly.

Abstract: The present arrangement is a hot zone structure for a vacuum furnace which includes an endlessly shaped outside wall (e.g. shaped substantially into a circle) preferably made of stainless steel. Disposed next to the inside surface of the outside wall is a layer or layers of heat insulating material means such as graphite felt. Further disposed next to the inside surface of the insulating material means is an inside wall preferably made of graphite. The inside wall defines the chamber of the hot zone structure into which items to be heat treated are placed. Passing through the outside wall, through the layer of heat insulating material, and through the inside wall are many continuous apertures. At the end of each continuous aperture there is located a threaded terminal piece and threaded into each terminal piece is a graphite nozzle. Accordingly there is a plurality of graphite nozzles passing from outside the outside wall of the hot zone structure through into the inside chamber of the hot zone structure.

Abstract: The present invention includes a heat insulation wall which is formed in a closed plane configuration, such as a circle, and which has first and second pairs of apertures formed therein to accommodate cooling (inert) gases which are introduced into the heat chamber defined by said insulation wall. The cooling gases pass into the heat chamber and out of the heat chamber through the first and second pairs of apertures to cool a workpiece which has been heat treated. The pairs of apertures lie (in pairs) opposite one another on the periphery of the heat insulation wall. Outside of the heat insulation wall, lying opposite the first pair of apertures, is located a heat reflecting member and opposite the second pair of apertures, outside of the heat insulation wall, there is located a heat reflecting baffle. Accordingly when the heat chamber is operating in a heat treating mode any heat which passes through an aperture or a pair of apertures is reflected back through said apertures into the heat chamber.

Abstract: The present invention employs a heating element means which is formed into an endless configuration, i.e., a closed plane, circular configuration, loop, etc. In a preferred embodiment the heating element means comprises a molybdenum strip although a plurality of molybdenum sections, which are secured to one another to make up a continuous sectionalized strip could be used. When such a strip conducts electrical current there is heat generated (I.sup.2 R) and such heated strips are the source of heat for the hot zone chamber of a vacuum furnace. There are a number of such continuous strips which make up the overall heating element means for a hot zone chamber. The continuous strips, or heating elements, each has first and second terminal means secured thereto at respectively first and second different locations, so that between said first and second terminals there exist two separated electrical current paths, or a bifurcated path.

Abstract: The present invention is a duct arrangement for use with a vacuum furnace to permit inert gas to be supplied continuously to the hot zone enclosure of a vacuum furnace. The novel duct arrangement includes a plenum means that, in the preferred embodiment, is formed so that its inside wall is the outer wall of the hot zone enclosure and which is disposed to be wrapped around 95% of the hot zone enclosure (within the vacuum chamber) with which it is employed. The plenum is sealed at both ends and is formed to have a plurality of holes in the common wall of the hot zone enclosure and the plenum. Into each of said holes there is fitted a removable nozzle member. A relatively large hole is formed in the outside wall of the plenum to permit inert gas to be fed into the plenum and through the nozzles into the hot zone enclosure to cool the work piece therein.